1 Abstract—In this paper interference channel with common information and two confidential messages is investigated. There are two senders that need deliver their privative messages and a certain common message. The private messages must be confidential in their corresponding receivers. An achievable rate region and an outer bound for such a channel are obtained and it is shown that these rate regions include some existing results for some related channels. Index Terms—Capacity-equivocation region, common information, confidential messages, secrecy rate region, rate- equivocation region I. INTRODUCTION NTERFERENCE channel (IC) is a fundamental building blocks in communication networks which is appear when signals intended for one receiver, supposed as interference for the other receivers. A key question in this setting is how to conquest of interfering signal which is made in simultaneous transmissions; despite many attempts is an open problem in general case. For more detail see, e.g., [1] and the references therein. One of the problems caused of nature of these channels is secrecy issues. It is because of the fact that the information can be extracted by the other nodes that are not destined. In this case it is decided to minimize the leakage of information in non-destination nodes i.e., eavesdroppers. It is also needed to assess the security level of confidential information for the IC and study the achievable communica- tion rates under a specific secrecy constraint [2]. A special scenario in which both senders intend to transmit not only their privative information but also certain common information to their corresponding destination is recently considered. Interference channel with common information (ICC) was first studied by Tan in his original paper [3], where outer and inner bounds on the capacity region have been derived and it has been shown that the results includes some prior results. In [1] an achievable rate region for general two user ICC is derived. Also the authors in [1] proposed an encoding scheme that extended the Carleial’s successive encoding for ICC in [3], which allowed common information to be conveyed through the channel in a cooperative channel. In this paper, we consider two-user interference channel with common message in which each senders’ have private message that must be secure in unintended receiver (Fig. 1). We establish the capacity-equivocation region for ICC channel and we show that the capacity-equivocation region reduces to the capacity region of ICC in [1]. Furthermore we show that in special case our region reduces to capacity of cognitive interference channel with secrecy was studied in [2]. The rest of the paper is organized as follows. In Section II we introduce the model of ICC channel with confidential messages. In Section III, we present the capacity-equivocation region and discuss the relations between our achievable rate region and several existing results in [1] and [2]. Finally we conclude in Section IV. II. CHANNEL MODELS In this section we present the channel models of the ICC based on the models introduced in [1]. Definition 1: Let  denotes a discrete memoryless interference channel consists of finite alphabets   ,  ,  ,   where   and   ,  = 1, 2, denote channel input and output respectively and  denotes the collection of the conditional probapilities   ,  |  ,   on y  ,y  ∈   ×  given   ,  ∈  ×  . The channel is memoryless and for  channel uses, we have   ,  |  ,  =   ,  |  ,     (1) where   =   ,…,  ∈   and   =   ,…,  ∈   for  = 1, 2. The marginal distribution of   given by     |  ,  =     ,  |  ,   " #$ ∈ #$ (2) Secrecy Rate Region in the Interference Channel with Common Information Hamid G. Bafghi * , Somayeh Salimi † , Babak Seyfe * , Mohammad R. Aref † . * Department of Electrical Engineering of Shahed Univ. Tehran, Iran, Email :{ ghanizade, seyfe}@shahed.ac.ir *† ISSL Laboratory, Electrical Engineering Department, Sharif University of Technology, Tehran, Iran. Email: {salami@ee.sharif, aref@sharif}.edu I 1 0 ˆ , ˆ W W 2 0 ˆ , ˆ W W 1 Y 2 Y ) , ( 1 0 1 W W X Ρ 1 W 0 W 2 W ) | ( 1 2 n y W H ) | ( 2 1 n y W H ) , ( 1 0 1 W W X Fig. 1. The interference channel with common message and two confidential messages.